The Windows 7 language packs can be installed only from the Optional Updates section in Windows Update. However, these language packs are not available on the Microsoft Windows Server Update Services (WSUS) server or through the Microsoft Download Center.
Follow the given instructions for installing the Windows 7 Language Pack:
STEP 1: You can access the Control Panel through the Start Menu 
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STEP 2: Then select Change Display language under the Clock, Language, and Region Box. If you’re in Classic View, select Regional and Language Options.
STEP 3: Make sure you’re on the keyboards and Languages tab and click on Install/Uninstall Languages.
STEP 4: Select the 2nd option and locate to your DVD drive or where you had previously extracted the ISO. You only need to move to the directory in which the windows 7 language pack is in. For some reason, the ISO doesn’t show up as a selectable option. (Microsoft may offer these language packs as optional updates in the near future).
STEP 5: Click Open and Windows will automatically search the language pack. You need to accept the End User License Agreement (EULA) and Install the Language Pack. This may take several minutes.
STEP 6: Once you’re completed, you’ll be prompted if you want to switch to the installed language pack.
Whenever you change language packs, you will have to log off and log back in for the changes to take into effect. In the future when you want to change language packs that have already been installed, go back to the “Keyboards and Languages†tab under Regional and Language Options and you should be able to select from a menu of different language packs.
